Stop Mirai Botnets: AWS WAF + API Gateway Security Playbook

If you run APIs — whether for a startup, SaaS platform, or a simple e-commerce integration — you already know they’re the lifeline of modern digital businesses. APIs connect apps, customers, and partners. But with openness comes vulnerability.

Among the most notorious threats is the Mirai botnet. Originally infamous for hijacking insecure IoT devices, Mirai and its variants continue to fuel massive DDoS attacks worldwide. For API owners, this can mean thousands of malicious requests per second, skyrocketing AWS bills, downtime, and unhappy customers.

The good news? AWS provides powerful tools like WAF Web ACLs and API Gateway throttling to keep your APIs safe.

This playbook will walk you step-by-step through how Mirai works, why it’s so dangerous, and exactly how to use AWS WAF + API Gateway to stop botnets in their tracks.

By the end, you’ll know how to protect your small shop or global enterprise API without overspending — and with confidence.

What Is Mirai?

Mirai is a botnet built by infecting IoT devices like routers, IP cameras, and even printers. Once compromised, these devices become “zombies” controlled remotely by attackers. At its peak, Mirai powered some of the largest DDoS attacks in history, including the 2016 Dyn outage that disrupted Netflix, Twitter, and GitHub.

Why Mirai Is a Threat to APIs

Unlike a single attacker, Mirai can unleash traffic from hundreds of thousands of devices simultaneously. For APIs, this means:

• Overwhelming your endpoints with fake traffic
• Skyrocketing AWS bills (since every request is billed)
• Locking out real users and partners
• Damaging your brand reputation with downtime

Even if your business is small, Mirai doesn’t care. Attackers scan the entire internet for exposed endpoints and weak defenses.

A Small Shop Analogy

Imagine you run a small online store with 10 trusted suppliers. Each supplier sends one API request daily to update inventory. Everything runs smoothly.

One day, you wake up to find:

• 1000 requests per second hammering your API
• Requests from 500+ random IPs across the globe
• None of them belong to your suppliers

Your API Gateway bill explodes. Customers can’t check stock. Partners can’t update shipments.

You’ve just been hit by a Mirai botnet attack.

How AWS WAF and API Gateway Help

AWS offers a set of native, cost-effective tools that make it possible to block Mirai-like botnets before they cripple your systems.

1. AWS WAF (Web Application Firewall)

• Lets you define Web ACLs (Access Control Lists)
• Supports IP whitelisting and blacklisting
• Blocks requests at the edge before they hit your API Gateway

2. API Gateway Throttling

• Controls how many requests per second are allowed
• Protects your backend services from overload
• Keeps costs predictable by preventing excessive usage

3. API Keys + Usage Plans

• Assign API keys to trusted partners
• Enforce quotas and rate limits
• Monitor who is accessing your API

Together, these three tools create a layered defense — essential for dealing with distributed attacks like Mirai.

Step-by-Step Playbook: Stopping Mirai with AWS

Step 1: Identify Trusted IPs

List out the known IP addresses of your suppliers, partners, or clients. These are the only requests you want to allow.

Step 2: Configure WAF IP Whitelist

1. Open AWS WAF Console → Create Web ACL
2. Scope: Regional (to match API Gateway)
3. Create an IP Set → Add supplier IPs
4. Add a rule → Match source IP → Action: Allow
5. Default action = Block
6. Associate ACL with your API Gateway

Result: Only your suppliers get through. Mirai botnet traffic is blocked at the edge.

Step 3: Enable API Gateway Throttling

1. Go to API Gateway Console
2. Choose the API → Stages → Default Stage
3. Set Rate Limit (e.g., 10 requests/second)
4. Set Burst Limit (short spikes allowed)

Result: Even if traffic spikes, your backend stays functional.

Step 4: Create Usage Plans & API Keys

1. Go to Usage Plans → Create Plan
2. Define limits (e.g., 1000 requests/month per supplier)
3. Generate API Keys and distribute to suppliers
4. Monitor usage in CloudWatch

Result: You know exactly who is using your API and how much. Abuse is eliminated.

Step 5: Monitor & Adjust

• Use CloudWatch metrics to monitor traffic
• Adjust limits as your business scales
• Regularly review WAF rules and API keys

The Business Impact of Botnet Attacks

Financial Costs

At 1000 requests/second, your AWS API Gateway bill can skyrocket in hours.

Availability Risks

Real customers and partners can’t access your services, leading to lost sales and broken trust.

Reputation Damage

Downtime makes you look unreliable — and recovering customer trust takes much longer than fixing APIs.

By setting up AWS WAF + API Gateway correctly, you avoid these costs and keep your business running smoothly.

Real-World Lessons

• Mirai isn’t theoretical. It has already taken down Fortune 500 companies.
• Small businesses are not exempt. Attackers don’t discriminate — they scan IP ranges for any open target.
• Defense doesn’t have to be expensive. AWS WAF + API Gateway usage plans are far cheaper than global CDN or enterprise-grade tools.

Bullet Points / Quick Takeaways

• Mirai botnets hijack IoT devices to launch massive DDoS attacks
• APIs are attractive targets because each request costs money
• AWS WAF blocks unwanted traffic before it reaches your API
• API Gateway throttling + usage plans protect your backend and costs
• Layered defense ensures resilience, availability, and trust

Call to Action (CTA)

Don’t let a botnet crash your APIs or inflate your AWS bill.

👉 Start implementing this AWS WAF + API Gateway playbook today. Secure your endpoints, protect your partners, and build customer trust.

For expert guidance, reach out to our cloud security team and get a tailored AWS defense strategy for your business.

Optional FAQ Section

What is the Mirai botnet?

Mirai is a malware that infects IoT devices and uses them to launch DDoS attacks, overwhelming systems with fake traffic.

Why are APIs vulnerable to botnets?

APIs are publicly exposed and billable per request. Botnets can flood them with fake traffic, causing costs to spike and services to crash.

Do I need CloudFront or Shield Advanced?

Not necessarily. For many small and medium businesses, AWS WAF + API Gateway throttling provides sufficient protection. Larger enterprises may still add CloudFront or Shield.

How much does AWS WAF cost?

Pricing is based on Web ACLs and rule evaluations. For small setups, costs are typically just a few dollars per month — much cheaper than absorbing botnet traffic.